Insurance Company Regulatory Requirements Insurance Company Regulatory Requirements (Details 1) (USD $)					3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended
	Sep. 30, 2013 MAC	Jul. 16, 2013 AGBM	Sep. 30, 2013 MAC Holdings	Jul. 31, 2013 MAC Holdings	Sep. 30, 2013 AGM	Sep. 30, 2013 AGM	Sep. 30, 2013 AGM	Sep. 30, 2013 AGM New York	Sep. 30, 2013 AGC	Sep. 30, 2013 AGC	Sep. 30, 2013 AGC	Sep. 30, 2013 AGC Maryland	Sep. 30, 2013 AGC Maryland	Sep. 30, 2013 AGM and AGC	Sep. 30, 2013 AGM and AGE New York
Statutory Accounting Practices [Line Items]
Capitalization of subsidiary, statutory basis	$ 800,000,000
Intercompany loan		82,500,000	300,000,000		100,000,000	100,000,000	100,000,000
Holding company's percent ownership of common stock				100.00%
Subsidiary percent ownership of common stock							61.00%				39.00%
Payment for interest in subsidiary					425,000,000				275,000,000
Statutory surplus, balance	400,000,000
Intercompany, ceded premiums						87,000,000,000				24,000,000,000
Intercompany, ceded unearned premiums						468,000,000				249,000,000
Contingency reserves reassumed, remainder of year, percent												33.00%		33.00%	33.00%
Contingency reserves reassumed, remainder of year, amount												$ 267,000,000			$ 250,000,000
Contingency reserves reassumed, year two, percent												50.00%			50.00%
Contingency reserves reassumed, year three, percent												17.00%			17.00%
Threshold for dividend payments as percentage of policyholder' surplus								10.00%					10.00%
Threshold for dividend payments as percentage of adjusted net investment income								100.00%					100.00%